As one of the most important equipments in current working environment, imaging device has become an essential equipment for offices or homes. Generally, a plurality of computers share one imaging device such as a printer, a scanner and the like, for resource conservation.
Taking the printer for example, a plurality of computers can use one common printer for imaging usually by means of sharing, that is, a first computer which is connected with the printer provides the printer with property of sharing by setting the device attributes, and based on the sharing mode, a second computer controls the printer via the first computer, thereby to implement printing tasks. However, this operation mode is under the condition that the first computer has to be in a working state, obviously, keeping the first computer in working state just for enabling the second computer to print will lead to energy waste.
To solve the problem above, printer manufacturers have introduced printers with multiple universal serial buses (Universal Serial Bus, USB), which can simultaneously connect to a plurality of computers, of which the specific structure is as illustrated in FIG. 1. In addition to a conventional imaging control unit 10, the imaging device also includes one USB control unit 20 and n USB interfaces 30, where the USB control unit 20 controls the data transmission of each USB interface 30, specifically the USB control unit 20 performs the changeover to control which USB interface 30 transmits data with the imaging control unit 10. N computers (PC) 40 utilizes n USB buses to connect to n USB interfaces 30 of the imaging device respectively, thereby realizing the communication with the imaging control unit 10.
In the foresaid mode, due to the existence of the situation that a plurality of PCs are simultaneously connected to the USB control unit for communication, it is possible to realize communication among multiple PCs via the USB control unit, however the security of user data in the PCs is threatened. Especially when the plurality of PCs belong to different networks, for example, when some PCs belong to a local area network (with requirement of encryption protection) and some belong to a public network, the local area network will be threatened by security risks in the public network, such as hackers filching data, computer virus attacking and destroying data, which will result in data lost, network breakdown, etc. in serious cases.